SDRAM Controller For Low-end FPGAs

There are very few ‘recent’ FPGAs out there that can be easily soldered. Due to their important number of IOs, they usually come in Ball Grid Array (BGA) packages. The Xilinx Spartan 6 LX9, a TQFP144 FPGA (having pins with a 0.5mm pitch) is one of the few exceptions that can be used to make low end development boards. However, it doesn’t have a lot of logic and memory resources or an on-chip Memory Control Block implemented in the silicon. Therefore, [Michael] designed an SDRAM controller with a small footprint for it.

Writing an SDRAM controller from scratch isn’t for the fainthearted – first of all you really have to know how SDRAM  works (RAS, CAS, precharges, refresh cycles), and because of the high speed and accurate timing required you also have to learn some of the finer points of FPGA off-chip interfacing. In addition, most publicly available open cores are very complex – for example just the RTL core of the sdr_ctrl controller on opencores.org adds up to over 2,700 lines of Verilog. Even if it is not an accurate comparison metric, [Michael]’s controller is only 500 lines long.

Machine Metabolism: Structure-Reconfiguring Robots

truss reconfiguring robot

It might be difficult to tell from the picture, but you’re looking at a robot that is capable of building and disassembling simple truss structures. We’ll let that sink in for a moment.

[Jeremy Blum] finished his metabolic machine research back in 2011, but just this month has had his journal paper published in the IEEE Robotics and Automation Magazine on Structure-Reconfiguring Robots.

The concept behind this robot is biological metabolism – the ability to break down nutrients into building blocks, and then to use them to build new things. What if we could build a robot to emulate this most basic aspect of biology? Well, they have. Take a moment to imagine the implications in space: a fully automated deployment (or repair) of large structures. Or back on earth, large radio towers that are automatically assembled, welded, and even repaired if need be. The possibilities are amazing.

To see the Structure-Reconfiguring Robot in action and to learn a bit more about how it works, check out the video after the break.

Continue reading “Machine Metabolism: Structure-Reconfiguring Robots”

Hovercraft Plane?

[Rudy Heeman] has been working in his garage on what we may consider a new class of vehicle. It’s a hovercraft —  but it also has wings.

That’s right, you drive it on ground, water, and you can even take flight with it! However, it’s far from a new idea. After doing some digging it appears the first type of this vehicle was actually tested back in 1996 by Universal Hovercraft — a quick peruse of their site reveals you can even buy your own kits to make one! Regardless of where it came from, or who made one first, it’s a brilliantly fun concept, and would be a blast to fly. Oh and you don’t even need a pilot’s license, it’s considered a boat and follows the same rules and regulations for boating.

Stick around after the break to see one in action! Now all we need to do is figure out how to combine one of these with a Delorean Hovercraft!

Continue reading “Hovercraft Plane?”

LED Blinds Turn Windows Into Displays

[Dinofizz] is almost done with his vertical LED blinds. The build makes use of 768 diffused white LEDs (10mm size), at a resolution of 48×16, and it only requires one 16-channel LED driver (a MBI5026), which makes use of 3x 4-to-16 demultiplexers. Did we mention it has 16 shades of grayscale too?

At the heart of the many piles of painstakingly soldered wires is an ATmega644A microcontroller which takes care of interpreting the data for the display. He didn’t write the firmware himself though, that credit goes to [Jay Clegg] who does some pretty cool work with Evil Mad Science’s Peggy 2.0 LED driver.

What we really have to admire is the amount of effort he put into this project. He used custom PCBs to daisy chain the blinds together, 300 feet of 16-way ribbon cable, and approximately 4000 individual solder joints! You’d think there would have been an easier way!

Making use of his high rise windows, he now has the ability to broadcast messages for the world to see. After the break check out the video of them in action!

Continue reading “LED Blinds Turn Windows Into Displays”

[Ben Krasnow] Explains Kilowatt Hour Meters

benkrazpowermeter

[Ben Krasnow] is back, and this time he’s tearing down a kilowatt hour meter (kWh). While not as exciting as making aerogel at home, or a DIY scanning electron microscope, [Ben’s] usual understated style of explaining things makes a complex topic simple to digest.

These old mechanical meters have been a staple on the sides of houses and businesses since the dawn of commercial power. We always thought the meters were a basic electric motor. Based upon [Ben’s] explanation though, these meters are a complex dance of electromagnetic fields. Three coils create magnetic fields near an aluminum disk. This creates eddy currents in the disk resulting in a net torque. The disk spins, turning a clockwork and advancing the dials.

Why three coils? One is a high turn high gauge voltage coil, and the other two are low turn low gauge current coils. The voltage coil has to be phase shifted 90 degrees to create the proper torque on the disk. Confused yet? Watch the video! [Ben] does a much better job explaining the field interactions than we could ever do in text.

Continue reading “[Ben Krasnow] Explains Kilowatt Hour Meters”

Cuba: A DIY Society?

ScreenShot041

After the U.S. left Cuba back in the 60’s, most of the engineers went with them, so [Fidel Castro] told the citizens to learn how to make stuff themselves. They were called the National Association of Innovators and Rationalizers (ANIR), and that’s exactly what they did. This was the beginning of Cuba’s backyard innovation.

Fastforward a few decades and the 90’s were a very difficult time for Cuba. With the collapse of the Soviet Union in 1991, a severe economic downturn almost crippled the country, and as a result a Cuban DIY culture began to flourish even more — out of absolute necessity. No money, no imports, only what they already had. Making and fixing things became a part of life, you couldn’t just go out and buy a solution to your problem, you had to do it yourself. This might be one of the greatest examples of what a full-flung maker/DIY society would be like — well, maybe minus the communist part.

The excellent video after the break is a short story about the designer [Ernesto Oroza], who started collecting examples of this DIY culture under his art project aptly called, Technological Disobedience. It’s worth the watch, so take a look.

Continue reading “Cuba: A DIY Society?”

Fail Of The Week: Photography Turntable

Turntable photography has seen a rise in popularity driven by online shopping. If you can’t hold it in your hand at least you can see what it looks like from all angles. From the still image, [Petteri Aimonen’s] roll-your-own turntable looks great. It’s completely enclosed and has a very nice paint job. But when you see it in action it appears to suffer from a stutter.

Continue reading “Fail Of The Week: Photography Turntable”